1. Field of the Invention
This application concerns an overhead camshaft type engine with an elongated multi-part valve actuator assembly between the camshaft and the valves. The actuator assembly has one end pivotally connected to a shaft and an opposite end engaged against an upper end of an engine valve. The construction of the multi-part actuator assembly allows rotation near its mid-portion adjacent to a roller follower supported for engaging a camshaft lobe. The cylinder head supports an extendable lash adjuster which urges the roller follower into engagement with the camshaft lobe.
2. Description of Related Art
The U.S. Pat. No. 4,848,285 to Konno, dated July 18, 1989, discloses a solid (single part) rocker arm 7 (9) for a valve 1a (1b) and as operated by lobe portion 3. Another solid (single part) rocker arm 8 engages the valves and is controlled by lobe 5. There is no teaching of a multi-part rocker arrangement nor the use of a hydraulic lash adjuster to urge a pivotally connected rocker against a cam lobe and a valve end surface.
The U.S. Pat. Nos. 4,607,600; 4,611,558; and 4,612,887; 4,617,880 to Yoshizaki, disclose a multi-part rocker arm which is foldable at a midpoint when a locking pin is moved to selected position. When the locking pin is moved to another selected position, the two main portions of the rocker arm are formed into a solid (non-foldable) rocker arm configuration. The purpose of these devices is to render certain valves inoperative at a given engine condition. Likewise, U.S. Pat. No. 4,844,023 to Konno discloses a similar arrangement for the same purpose.
The U.S. Pat. Nos. 4,498,432 and 4,526,142 to Hara et al. disclose multi-part rocker arms in which two members are positioned one on top of another. In combination with a selectively extendable lash adjuster, the combination of members proves variable valving action by altering the fulcrum.